New Concepts in Exploring Subsalt Paleozoic Hydrocarbon Systems in Mature and Near Producing Areas of Morocco

H. Jabour, A. Demnati, M. Hcaine, and M. El Alji

The subsalt Paleozoic hydrocarbon systems are one of the areally largest and paradoxally the least drilled in Morocco. Although, worldwide, these systems contain the largest potential gas reserves and contain one of the largest emerging oil plays and better still the few wells drilled to test the system in Essaouira Basin are producing commercial wet gas, these systems have never been tested in the Interatlasic and Prerif Basins. impediments to exploration in these areas focused on the inability to map beneath the "geophysical basement", to seismically image sub-salt, pre-Jurassic block faulted structures and the perceived lack of adequate source rock.

Recent integrated study combining newly acquired deep targeted seismic, gravity, magnetic, geochemical data and basin modelling techniques, has permitted to decipher the pre-salt structures, interpret basin evolution and assess source rock potential. The sub-salt Paleozoic hydrocarbon system evolved in basically five stages: (1) simultaneous sediment accumulation and structural formation during the Paleozoic; (2) major tectonism and erosion in Late Paleozoic (Hercynian); (3) Triassic-Lower Jurassic deposition of a regional seal (salt and evaporite); (4) Mesozoic charging primarily from Silurian to Carboniferous sources; and (5) re-initiation of generation from Silurian source in uplifted blocks following atlasic (Neogene) compression.

Large structures and prospective stratigraphic features exhibiting many similarities to the prolific Triassic objectives of neighboring Algeria are now defined and await to be drilled. Furthermore ,the Maghreb-Europe gas pipeline will shortly cross both the Interatlasic and the Prerif areas providing additional positive attribute that makes these exploration areas more attractive

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California